This invention relates generally to wireless communication systems, and more particularly, to wireless communication systems providing radio frequency (RF) communication.
Wireless communication systems may provide communication between individual users and/or between groups of users. For example, radio frequency communication between land mobile radios (LMRs) may allow messages to be communicated between two users or between a group of users. In particular, these LMR systems may be designed to support Push-To-Talk (PTT) services, such as a dispatch mode of operation, wherein a dispatcher from a central location communicates with one or more LMRs. In LMR networks, PTT services are often configured for operation in connection with defined or predetermined workgroups. For example, a police department or fire department may be designated as separate workgroups such that communications are provided to all registered members of that workgroup. For communication purposes, workgroups further may be organized into talk groups, which are typically smaller subsets of the workgroups. For example, a particular unit in the police department or fire department may form a workgroup. In operation, radio users and/or dispatchers key up PTT on a talk group. The LMR network is configured such that all members of the workgroup receive the communications being broadcast on a particular talk group (e.g., multicast communication). Additionally, an LMR that is registered, for example, in a police workgroup and that receives police workgroup broadcast communications also may listen in on and receive communications from a fire talk group.
LMR systems also may communicate using Internet Protocol (IP) messages. These IP based systems provide improved interoperability. However, in operation, a single voice stream is unicast to each of multiple users, for example, to each user in a talk group. This unicast transmission of IP messages can heavily load system resources by using a large amount of bandwidth, particularly when a large number of users are participating in a communication. Some systems may not have sufficient capacity to serve all users. Accordingly, communication delays or slow downs may result during group calls. The delays or slow downs may be propagated throughout the network, thereby affecting the overall system and/or communications between others users within the system.